Modifying warmups

[bctrackboi11]

I have spent the better part of the last day trying to figure out how to properly edit the warmups. Am I supposed to export them as a different file other than .dds? I've been having trouble with this, when I imported my newly made custom warmup, it showed up, but the warmup it replaced also showed up through it in some weird transparent thing. Anybody know the solution to this?